1. The simple answer is that Leviticus provides both universal laws as well as laws specifically for Israel (i.e. the Jewish people). The dietary laws are in the section regarding specific Jewish laws. The laws regarding homosexuality are in the section regarding universal laws. 2. For Christians, the New Testament specifically nullifies Jewish dietary laws while it reinforces the universal laws regarding sexual morality. 3. The “dietary law” argument has no force for an orthodox Jew. They do believe eating lobster is wrong so the equivocation has no effect. 4. If the argument is attempting to prove homosexuality is moral, it’s fallacious. It’s a mix of the ad hominem tu quoque and genetic fallacies. Their argument is: 1. The Bible says homosexuality is wrong.
2. The Bible says eating lobster is wrong.
3. We reject that eating lobster is wrong.
4. Therefore we must reject that homosexuality is wrong. That’s the same as saying: 1. A scientist proposes hypotheses A and B.
2. We have grounds to reject hypothesis A.
3. Therefore we must reject hypothesis B. Hypothesis B must be evaluated on its own merits. Even if we granted the first three premises of their argument, their conclusion does not follow. Homosexuality must be evaluated on its own. If they are trying to make an argument that the Bible isn’t true or that religious people are hypocritical, that’s another matter entirely. In any case, it is not a valid argument on the morality of homosexuality. Even if the Bible were a complete lie and every religious person were a hypocrite, homosexuality could still be immoral.